# Evaluation of a function

Calculator of f(x0)
Function variable (one letter)
To multiply, use a*b not ab

This handy tool allows you to calculate the value of a function for a given value of its variable. For example, if you have a function f(x), and you want to know the value of f when x = 5, our calculator will provide you with the answer.

### Form Usage Guide

To use the calculator, follow these simple steps:

1. Variable: Enter the main variable of your function. For example, for f(x), enter x.
2. Function: Enter your function. For example, x^2 + x + 1.
3. Variable Value: Enter the value for which you want to calculate the function. For example, 5.

### Examples and Practical Cases

Here are some examples to help you better understand how to use the calculator:

• For the function f(x) = x^2, and the value x = 4, the output will be 16.
• With f(x) = 2*x + 3 and x = 5, the result will be 13.
• If you have f(x) = sin(x) and x = pi/2, the calculator will display 1.

### Common Errors and Their Corrections

Be aware of these common errors:

• Forgetting * for multiplication. For example, "ax" should be written as "a*x".
• Forgetting parentheses in complex expressions, like sin(x + pi/2) instead of sin x + pi/2.

### Table of Functions and Operators

Variables A function can have one or more variables, but only one main variable. A variable is a single lowercase or uppercase letter. Examples: A function f with one main variable : f(x) = 4*x A function g with one main variable x and a secondary parameter m, g(x) = 4*x*m + x + 1,In this case, enter x in the “main variable” field Use a dot as decimal separator + (addition), - (substration), * (multiplication), / (division), ^ (power), For multiply operator, enter a*b not a.b nor ab. Example: 2*x. You may use these constants : pi (approx. 3.14), e (approx. 2,72) Examples: f(x) = pi * x or f(x) = e * (x+1+2*e)2 You may use theses functions in the expression of f(x) sqrt(x) (square root), exp(x) (exponential function), log(x) or ln (natural logarithm), You may use theses functions in the expression of f(x) sin (sine), cos (cosine), tan (tangent), cot (cotangent), sec (secant), csc (cosecant), You may use theses functions in the expression of f(x) arcsin (arcsine), arccos (arccosine), arctan (arctangent), arccot (arcotangent), arcsec (arcsecant), arccsc (arccosecant), You may use theses functions in the expression of f(x) sinh (hyperbolic sine), cosh (hyperbolic cosine), tanh (hyperbolic tangent), coth (hyperbolic cotangent), sech (hyperbolic secante), csch (hyperbolic cosecant) You may use theses functions in the expression of f(x) asinh (inverse hyperbolic sine), acosh (inverse hyperbolic cosine), atanh (inverse hyperbolic tangent), acoth (inverse hyperbolic cotangent), asech (inverse hyperbolic secant), acsch (inverse hyperbolic cosecant)